Method and apparatus for drilling oil wells



March 7', 1933. D. DANA ET AL.

141111101) AND APPARATUS FOR DRILLING 011. watts Filed may 2, 1931 2 Sheets-Sheet 1 ""J 1/4" mes March 7, 1933.

D. DANA ET AL.

METHOD AND APPARATUS FOR DRILLING OIL WELLS 2 Sheets-Sheefi Filed May 2, 1931 Patented Mar. 7, 1933,

UNITED STATES- PlATENT OF FICE DBEXLER'DANA; or same mama, AND rmx A. moaean, or savanna: mas,

curroanu METHOD am) AIBPARATUS FOB DB ILLING 01L warms Application filed Kay 2,

.This invention relates in a general way to the art of drilling wells, and is more particularly related toa drilling method and apparatus whereby the drilling cost per well is greatly reduced. It is well known to those familiar'with the art that the cost of building an ordinaryderrick with foundations such as used in modern drilling operations is a major factor in the complete cost of drilling a well. It is also well known that in certain fields to obtain a maximum production from theoil zone it is necessary that the wells be situated close together, making it necessary to conv struct a great number of derricks for the pur .15

pose of draining a comparatively small territory. 'In some regions there are several oil drilled immediately/adjacentthe first well.

producing zones' or horizons situated one above, the other so that a well may be drilled to one zone and before the next lower zone can be reached this firstzone must either be drained of its oil oranother well must be The former procedure may prevent an operating'companyr'ea ching the second zone before another company has drained the second zone of its oil, or ifa secondary .structure is constructe it materially increases the cost of the'oil obtained from thesecond zone above what itscost would have been had the same derrick structure 1 been used to reach 'the underlying zone or zones. 7

' In some locations, the most productive oil' zones have been'found to be located below the ocean at an appreciable distance-from the v shore. In these territories it has become a practice to build piers out tofand above the oil zoneupon which the derrick structures are located. The construction of these. piers and the necessary underwater construction at tending the building of the derrick structure entails considerable expense, making the cost of the foundation and pier alone fntheneighborhood of from $50,000.00 to $100,000.00 per location. p p In other locations due to rough and rocky terrain the initial location and foundation costs in advance of actual drilling represent a large proportion of the total well costs.

It is the primary object of this invention to produce a'well drilling method whereby 1931. Serial no. 534,461.

a single derrick structure may be used in the drilling of two or more wells. J This object may be accomplished when the derrick structure is situated on' the ground by mere- 1 shifting the rotary table on the,derrick tibor so that the wells may be spuddedin or started in close relation with each other, and

if the wells are to terminate in the same zone it is preferable'that some "form of bit. ide be employed to direct the bore holes into angularly disposed relation with each other so that the different wells terminate in the 'ments through which the drill stem may be operated in drillingthe' difl'erent wells. This conductor pipe may be placed immediately upon the floor of the ocean in the case of an underwater well, or it may, in. either an underwater well or a well started from the surface of the ground, he placed in a large diamtter bore hole-which is rilled to a comparatively shallowdepth ow the surface of the ground or the derrick. These bore holes may be from several feet to several hundred feet in depth and, as pointed out above, if the different wells are to'ferminate in the same zone, it is preferable that some form of bit guide be situated at or near the bottom of the bore hole for directing the auxiliary bore holes into angular relation with each-other. Where the wells are to terminate in difl'erent zones, however, the deflecting gu de may not necessarily be' employed, u'nde which circumstances the difierent wells may terminate at a point situated vertically below thederrick. Under any circumstances it is important in the "practice of the method contemplated by this invention that the op: eration of 'the drill be carefully regulated through the use of varyingdrilling weights, methods, and apparatus (such as whipstocks), so that the second and subsequent procedure is so well known that it need not be further discussed here.

It is a further object of this invention to produce a novel type of easing or conductor tubing especially adapted for use in connec-' tion with this invention. It is a noteworthy feature of this casing or conductor tubing that it is provided with a divider or partitioning member which may be removably or fixedly mounted therein and the divider or partitioning member may be associated with a bit guide provided with bit deflecting surfaces which are arranged so as to cooperate with the compartments formed by the divider to direct the movement of the bit so that the bore holes produced thereby are arranged in angularly disposed relation with each other.

The details in the method and apparatus contemplated by this invention, together with otherobjects attending its production, will be best understood from the following description of the accompanying drawings which are chosen for illustrative purposes only, and in which Fig. 1 is a sectional elevation showing the lower portion of a derrick structure used in producing underwater wells and illustrating the manner in which wells of the type contemplated by this invention are produced;

Fig. 2 is a plan section which may be considered'as having been taken in a plane represented by the line 2-2 in Fig. 1;

Fig. 3 is a perspective view showing one form of bit guide which may be used in the method contemplated by this invention;

Fig. 4 is a small sectional elevation which is more or less diagrammatic and illustrates another manner of carrying out the invention;

Fig. 5 is a view similar to Fig. 4 illustrating still another manner of practicing the 7 process contemplated by this invention; and

Fig. 6 is a perspective view showing a modified form of bit guide.

More particularly describing the invention as herein illustrated, reference numeral 11 indicates a derrick foundation which is shown as comprising a base portion 12 which is built upon the shale 13 of the floor or bed of the ocean or other body of water and a hollow derrick supporting column 14 which rests upon the base portion 12 and supports the derrick floor 15. Reference numeral 16 indicates the lower portion of the derrick structure and reference numeral 17 indicates a pier by means of which the derrick struc-.

ture may be reached from the mainland. The

hollow column 14 is made so that its interior is sufficiently large to permit workmen to enter therein and in View of the fact that the base member 12 is situated on the floor of the ocean, it will be observed that this column is Water tight and must be made of suflicient strength to withstand the hydrostatic pressure and movement of the water surrounding it.

The derrick floor 15 carries a rotary table 20 of the usual type which is utilized. for the operation of a drill string for advancing the various bore holes beneath the derrick structure. In carrying out the process contemplated by this invention in connection with apparatus of the type shown in Fig. 1, the procedure followed'is to first drill a large diameter'b'ore hole as indicated by reference numeral 21. This bore hole may be from 30 to 50 inches in diameter and although it is hereinafter referred to as being of comparatively shallow depth, it will be understood that it may extend from several feet to several hundred 'feet beneath the surface at which it enters the formation. After the bore hole 21 has been advanced to the desired depth, a conductor tubing 22 is placed therein. The conductor tubing 22 may extend clear to the bottom of the bore hole 21, it may be driven a slight distance below the bottom 21, or it may terminate above the bottom of the bore hole 21 without departing from the scope of this invention.

As was pointed out in the fore part of the.

specification, in the event the various wells are to terminate in the same oil zone, it is preferable that these wells be'drilled so that they bear an angular relation with each other and consequently terminate in any one oil zone at appreciable distances one from the other. For the purpose of directing the course of the auxiliary bit or bits for producing the smaller diameter auxiliary bore holes, we propose to use a bit deflecting member at or near the lower end of the conductor tubing 22. This guide member is provided with a plurality of bit deflecting surfaces corresponding to the number of auxiliary bore holes which are to be produced and such surfaces are inclined outwardly at the desired angle for properly directing the course of the auxiliary bore holes. Reference numeral 23 indicates one form of bit guide which may be used in the process contemplated by this invention.

For the purpose of directing the movement of th,e bit so that it is finally brought into engagement with the proper deflecting surface, we find it desirable to use within the conductor pipe a divider or partitioning mem-- guide. The partitioning member or divider I may, therefore, be. installed prior to, during cr subse uent to the installation of the cou-v ductor plpe, or it might even be used independentlyof the conductor pipe. The num' r of these panels is such as to divide the conductor pipe intoa plurality of longitudinal compartments which correspond in numberto the number of bit deflecting surfaces on the guide member 23.

Referrin to Fig. 3 it will be noted that the bit guide is provided with outwardly sloping depressions 30, 30a and 306 which provide three bit deflecting surfaces in this member. The divider or partitioning member 24 is shown as comprising panels 31,3111 and 316 which are secured by means such as welding, to. the upper end portion of the-block 23 and are situated between the depressions 30, 30a and 306. In order that 'a bit advanced downwardly throu b any one of the compartments formed by t e panels will be directed into the corresponding depression and into engagement with, the bit deflecting surface therein, we provide the upper surface of the block 23 with rounded shoulders, as indicated by reference numeral 32, thus eliminating any square shoulders or right angle surfaces upon which the bitmight'be hung up.

In Fig. 1, reference numeral 35 indicates an auxiliary bore hole which has been drilled by means of a bit passing through the cofiipartment 36a of the conductor ipe 22. This bore hole is shown ashaving een complete and as containing a casing 37 which terminates at the upper .end ofHthe conductor pipe 22 where it is equipped with the usual type of fittings 38, through which the-oil is deliveredfrom the well in a pipe indicatedbyreference numeral 39.

' the mediunrof the rotary table 20 Reference numeral 40 indicates a drill bit which is shown as being in engagement with a deflecting surface 30 of the, bitguide 23. This drill bit is attached to'the lower end of a drill string 41 which passes downwardly through the compartment 36 in the conductor tubing 24 and is provided at-its upper end with a kelley 42 whereby it is rotated through It will be understood that in the'carrying' out of the process contemplatedby this invention, the rotary table is positioned with its directly above the central portion .of the-22:21am large diameter bore hole 21'during the drilling of this bore hole. When the auxiliarys bore hole such, as bore hole 37. and the ch isbeing produced by the bit 40;."

rotary table so that its. axis "is in line with the central portion of the compartment in the conductor tubing through which the auxiliary bore hole is to be drilled. The shifting pm I of the rotary table may be carried out in any well known manner and means for eflecting sucha shifting movement are'n'o part of this invention and are consequently not discussed 1 other directly j and are pre erably started by placing a guide member at the surface of the ground which may be pointed at its lower end and driven into the ground, as indicated by reference numeral 51.

In '5 we illustrate the manner in which the invention may be carried out in [drilling two or more bore holes to different levels to obtain oil from two or more-different oil producing zones below the same derrick structure 166? These bore holes are indicated by reference numerals 52 and 52' and. are shown as being substantially parallel. When this procedure is followed it may not be necessary to use a bit deflectin or directing member at the 'ground surface, ut as pointed out above, it is important that the drilling operations becarefully controlled so that there is no tendency for the course of any bore "hole to interfere with others drilled from the same derrick. v

Fig. 6 illustrates'a modified form ofbit directing and bit guiding member which is shown as comprising panels 24' between which deflecting blocks 23' are mounted.

It is to be understood that while we "have herein described and illustrated one preferred \procedure and certain preferred forms of prises: drilling a comparatively shallow large diameter bore hole placing a partitioned conductor pipe in said bore hole; and drill-- ,ing a plurality of small diameter bore holes in the compartments formed by the insaid conductor pipe.

partition 2. A well drilling method which comprises: i

having a plurality of bit'deflecting surfaces in the bottom of said bore hole; and advancirig a small-diameter bit into said large-d1-' I anifeter bore hole successively past different gadrilled, it is; advisable to shift the deflecting surfaces on fsaid directing member drilling a comparatively shallow large di-' ameter bore hole; placing adirecting member to form a plurality of angularly disposed small iameter bore holes at the bottom of said large diameter bore hole.

'3. A well drilling method which comprises drilling a comparatively shallow large di- 4. A method of drilling a well below a g body of water which comprises: building a foundation on the bed of said body of water; mounting a drilling derrick structure on said foundation; drilling a large diameter bore hole through said foundation; placing aconductor pipe in said large diameter bore hole; and drilling a plurality of small diameter bore holes from said large diameter bore hole at the bottom of said conductor casing.

5. For use indrilling oil wells: a conductor casing; a divider in said conductor casing separating the conductor casing into a plurality of longitudinal passages; and a directing member at the lower end of said conductor tubing having a bit deflecting surbody of water which comprises: building a foundation on the bed of said body of water; mounting a drilling derrick structure on said foundation; and drillinga plurality of angularly disposed bore holes below said foundation.

13. A well drilling method which comprises the steps of: building a single derrick structure; utilizing said derrick structure to face positioned substantially in alignment with each of'said longitudinal passages.

6. For use in drilling oil wells: a bit guide having a plurality of angularly disposed bit deflecting surfaces formed thereon.

7. A bit guide of the class described embodyfng: a block formed with a plurality of bit deflecting surfaces thereon.

8. A bit guide of the class described embodying: a block provided with -a plurality of angularly'disposed sloping depressions to form bit deflecting surfaces which diverge outwardly toward the bottom of the block; and divider plates secured to the upper end of said block' between said depressions.

'9. For use in drilling oil wellsza con-' i ductor casing; and a bit guide at the lower end of said casing, said guide being pro vided with a plurality of angularly disposed bit deflecting surfaces.

10. A well drilling method which comprises: drilling a comparatively shallow large diameter bore hole; partitioning said hole to form a plurality of longitudinal chambers; and drilling a small diameter bore hole through each of said chambers.

11. A method of drilling wells below a body of water which comprises: building a foundation on the bed of said body of water;

mounting a drilling derrick structure on said foundation; and drilling a plurality of bore holes directly below said foundation.

12. A method of drilling wells below a 

